Bus bars for carrying multiphase electrical current for distribution throughout a building or facility are conventionally arranged one above each other in a duct or housing and extend parallel to the longitudinal axis of the duct or housing. Access to the bus bars for taking power off the duct is provided through an opening in the duct by means of a plug-in brick.
A typical bus bar arrangement comprises, from top to bottom, ground, A phase, B phase, C phase, and neutral. Plug-in openings may be spaced about two feet apart in the front and the rear panels of the bus bar housing. Electrical connections are made to the bus bars by way of stabs which are selectively attached in order to obtain the desired electrical system, for example, three wire, three wire with ground, four wire, four wire with ground, etc. The stabs are attached to the bus bars and extend outwardly through one of several compartments or cavities within the brick, which is mounted in a plug-in opening in the front and rear panel of the busway housing.
Many plug-in brick designs include a hinged or slidable door provided over the brick to close off access to the cavities of the brick when no plug-in unit is installed in the brick. In conventional designs, such doors may be easily opened and do not prevent unintentional access to the cavities of the brick. Furthermore, conventional brick cavities allow fingers or other objects of similar size to be easily inserted through the cavities and to come in contact with the electrical bus bars, which can result in severe injury.
A need therefore exists for a plug-in brick and cover assembly which deters unwanted access to the cavities of the brick.